With no tail, this animal is obviously shortened (5)
I believe the answer is:
rhino
'with no tail this animal is obviously shortened' is the definition.
'rhino' can be an answer for 'animal' (short for rhinoceros). I am unsure of the rest of the definition.
'with no tail this animal is obviously shortened' is the wordplay.
'with' is an insertion indicator.
'tail' means to remove the last letter (I've seen 'tailed' mean this (to tail something can mean to remove its end)).
'this animal' becomes 'rh' (I can't justify this - if you can you should give a lot more credence to this answer).
'shortened' says to take the initial letters.
The initial letters of 'is obviously' is 'io'.
'no' with its final letter taken off is 'n'.
'rh'+'io'='rhio'
'n' placed inside 'rhio' is 'RHINO'.
Can you help me to learn more?
(Other definitions for rhino that I've seen before include "Powerful herbivorous odd-toed ungulate, informally" , "Large African pachyderm" , "African/Asian ungulate" , "old money?" , "Horned jungle beast" .)